The present invention relates to a composition comprising an aqueous phase, a surfactant system and an oil phase. The surfactant system comprises one or more saponins, and lecithin.
The invention furthermore relates to a corresponding method of preparing a composition. Finally, the present invention relates to food formulations comprising a composition according to the present invention or obtainable according to a method of the present invention.
Compositions comprising an aqueous phase and an oil phase as well as a surfactant system are routinely used in the form of emulsions for making beverages. Typically, such compositions (beverage emulsions) comprise an aqueous phase comprising water, optionally one or more co-solvents and further ingredients. Within that aqueous phase an oil phase is dispersed in the form of microscopic droplets. The dispersed oil phase typically comprises flavorants (typically in the form of flavor oils) and optionally further lipophilic ingredients which are insoluble or only soluble to a very limited extent in the aqueous phase.
Compositions (like beverage emulsions) comprising an aqueous phase and an oil phase dispersed therein typically comprise a surfactant system which itself comprises one or more surfactants (emulsifying agents).
In particular when used for the preparation of beverages, compositions (emulsions) of the above described type have to meet a number of requirements. The emulsion must be stable, both in concentrated and in diluted (i.e. beverage) form. This stability should be maintained over a wide range of temperature and storage conditions. Furthermore, the emulsions should be simple to formulate and to incorporate into beverages.
As outlined in the literature, emulsion-type compositions for making beverages and other liquid foods are thermodynamically instable and therefore tend to separate into there original two phases (aqueous phase and oil phase). With respect to beverages, “ringing” and “sedimentation” are the typical effects associated with phase separation of an emulsion type composition. “Ringing” is the formation of a (whitish) ring around the neck of the beverage container, “sedimentation” is the precipitation of material at the bottom of the container.
Numerous emulsifiers have been tested and used in emulsion-type compositions for making beverages. In particular, gum Arabic, modified starch, and pectin have been employed. In an attempt to increase the stability of emulsion-type compositions for the preparation of beverages and other liquid foods microemulsions, i.e. emulsions comprising very small droplets of the dispersed (i.e. oil) phase, have been prepared and used. In addition to being typically more stable microemulsions additionally have the advantage of being transparent or clear when sufficiently diluted. Due to the very small size of the dispersed oil-droplets, which in many cases have a diameter of less than 140 nm, the visible light cannot be scattered. When such microemulsions are used as flavor delivery systems in food products, in particular in beverages, they must fulfill all the requirements discussed above. Additionally, they must of course also meet the various regulatory requirements with regard to their ingredients.
It is extremely difficult to prepare stable beverages comprising flavor oils and in particular citrus oils like lemon, orange and grapefruit oils. For the preparation of clear beverages, e.g. carbonated soft drinks, typically washed flavor oils are used in order to achieve the necessary water solubility. In this process, the unpolar substances of citrus oils (terpenes etc.) are typically washed out of the oil by adding a water/ethanol mix or propylene glycol to the oil. This mixture is slightly stirred and left in a tank at low temperatures of around 4° C. for 48 to 72 hours. A phase separation due to differences in density and polarity takes place. The polar flavor substances are enriched in the water/ethanol mix or in the propylene glycol, respectively, which is decanted from the rest and typically used as water soluble citrus washing to be added to clear soft drinks. This washing process is not very economic, takes in practice at least 3 days for production, and the smell or taste caused by and being characteristic for the unpolar flavor substances of the citrus oil is disadvantageously lost or reduced.
With respect to oil soluble vitamins like tocopherol (vitamin E) and coloring foodstuffs (colors) like carotene, a washing process is not feasible as the whole functional substance (vitamin, color) is needed in the beverage. Therefore, it is not possible to use these functional substances in clear soft drinks unless microemulsions based on emulsifiers like polysorbate are used, which however for certain purposes are not preferred as the emulsifiers are not of natural origin.
It was an object of the present invention to provide compositions which are stable micro-emulsions or can be transformed into stable microemulsions. It was a further object of the present invention to provide compositions that can be used as an oil-soluble-ingredient delivery system for making a food formulation having a certain property provided by the delivered ingredient. It was a particular object of the present invention to provide compositions which are capable of delivering flavorants, polyunsaturated fatty acids, vitamins and/or coloring food stuffs to a food formulation (and in particular to a food formulation being a beverage or a beverage concentrate). It was another object of the present invention to provide compositions which can be prepared in a relatively short period of time and without any complicated process steps.
It was another object of the present invention to provide a method of preparing such compositions. Preferably, it should be possible to conduct the method in a short period of time and without the need of conducting any complicated steps.
It was another object of the present invention to provide food formulations comprising compositions as discussed. In particular, a food formulation being a beverage should be provided which comprises a composition according to the invention and preferably is liquid and clear.
According to a first aspect, the present invention relates to a composition comprising                (i) an aqueous phase comprising        water,        one, two or more co-solvents selected from the group consisting of propylene glycol (1,2-propane diol), ethanol, triacetin (glycerin triacetate), and glycerol, and optionally one, two or more sugars, preferably selected from the group consisting of sucrose, fructose, and glucose,        (ii) a surfactant system comprising        one saponin or a mixture of two, three or more saponins, and        lecithin, and        (iii) an oil phase comprising (or consisting of)        one, two, three or more substances selected from the group consisting of flavorants, vitamins, coloring foodstuffs, and polyunsaturated fatty acids,        wherein the composition does not comprise a polyglycerol fatty acid ester.        